Rotary expansion-engine.



.R. EISERMANN. ROTARY EXPANSION ENGINE. APPucATlou FILED MAR. 25, 1913.

Patented Mar. 14,1916.

2 SHEETS-SHEET I.

THE COLUMBIA PLANOGRAPH 10.. WASHINGTON, D. c.

R. EISERMANN. ROTARY EXPANSION ENGINE.

APPLICATION FILED MAR. 25. 1913.

' Patented Mar. 14,1916.

2 SHEETS-SHEET 2.

UNITED sTATEs PATENT OFFICE.

RUDOLF EISERMANN, OF BERLIN, GERMANY, ASSIGN OR T0 RICHARD KLINGER, 0F GUMPOLDSKIRCHEN, NEAR VIENNA, AUSTRIA-HUNGARY.

ROTARY EXPANSION-ENGINE.

T 0 all whom it may concern:

Be it known that I, RUnoLF EISERMANN, a subject of the King of Prussia, residing at Berlin, Germany, have invented certain new and useful Improvements in Rotary Expan sion-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it ap pertains to make and use the same.

It is well known, that in rotary engines leakage is liable to occur between the Working parts, so that in working with expansion the actual expansion curve falls considerably below the'theoretical expansion curve. In some cases, particularly in small engines such as are used, for instance, in driving hand-drilling machines, rock drills, etc., by means of compressed air, the fall of pressure may be so great as to jeopardize the proper working of the machine. ing with expansion there is; generally the further difliculty, that in'certain positions the engine cannot start, because none of the working chambers communicate with the passage or conduit for the admission of pressure fluid. For this reason it was found necessary to provide a special reversing mechanism which enables the engine to start with full pressure, but which in the case of small engines implies an undesirable complication.

According to the present invention the said defects are avoided by providing narrow passages, 2'. 6. ports, grooves or slots which form a continuation of the passages or conduits admitting the pressure'fluid, so

that after the ordinary admission ports or passages have been closed, the said auxillary passages, e. the ports, grooves or slots allow a continuation of the supply of pressure fluid. ,The size of the said continuations is so calculated, that the supplementary flow of pressure fluid compensates the losses through leakage and thereby retains the expansion curve approximately at'its'theoretical height. At the same time the narrow-'continuations of'the admission conduits of the engine render it possible, that the engine may start in any position without necessitating means to adjust it for full pressure, because in the positions, in

which the principal admission ports are closed. suificient pressure fluid may passbe-' hind the pistons throughthe narrow con- Specification of Letters Patent.

In work- Patented Mar. 14., 1916.

Application filed March 25, 1913. Serial No. 756,719,

tinuations, for turning the engine until one I of the principal admission ports has been opened. I

The drawings illustrate by way of example a compressed air' engine embodying the invention. 7 r

Figure 1 is a. longitudinal section of the engine along line 1-1 of Fig. 2, Fig. 2 is a" cross section along line 22 of Fig. 1, seen from the right hand side. .Fig. 3 is a corresponding fragmentary section on a larger scale, looking from the left. Fig. 4 shows a sectionalong the circumferential surface of the piston drum, developed in the plane of the-drawing, together with the correspondingly developed controlling surfaces projected on a cylinder of the same diameter as thepiston drum. Figs..5 and 6 are sections on the lines 5.5- and 66 of Fig. 1 and Figs. 5 and 6? aresimilar sections in another position. Fig. 7 is a fragmentary section on the line 7-7 of Fig. 1'. Fig. 8 finally shows a modified constructional form of the invention. r V V In a casing is, the covers of which are provided with parallel cam surfaces cl, is mounted, by means of a hollow shaft'e, a revolving member in the form of a drum a, the end faces of which bear closely against the summits of the cam surfaces d. In radially cut longitudinal slots of the drum aare guided slides b, c which act as pistons and munioate alternately with the'openings f and g in the hollow drum shaft, when this latter revolves. The exhaust openingsl are situated in the jacket 70 of the casing.

In communication with each opening 5 of the stationary controlling member or valve and situated in the outer surface of this latter in a peripheral direction is a narrow groove 7' of such length, that the total opening consisting of the opening z'Iand the groove jis always in communication with one of the two corresponding openings 9 and By means of this arrangement the engine can be started directly even for example in the position shown in Fig. 2, because the motive fluid may pass through the grooves j behind the pistons and turn the engine at first to such an extent, that the opening communicates with the opening i in the controlling member or valve.

lVhen the engine is working at full speed, the quantity of motive fluid which passes through the extension j, after the inlet opening 2' proper has been cut off, is comparatively small in proportion to the quantity of motive fluid which passes through the opening a, owing to the high degree of throttling in combination with the high speed, and it replaces substantially only the losses due to leakage, so that the expansion. curve assumes a more or less normal course.

The supply of compressed :air to the interior of the controlling member or valve it takes place through the interiorcavity m of the inner stationary part 2 of a handle which is constructed as a receptacle for the lubricant. This handle has an oil chamber 19 between an outer jacket n and a sleeve 0 connected therewith, and an annular passage 7 separated from said oil chamber by a rib g.

In the direction of this annular passage an oblique passage .9 leads from the inner cav- I ity m. In a plane lying at right angles to the plane of the passage there is also located in the direction of the annular passage 0 an oblique passage 6 which passes over into an axial passage it which forms a continuation of the interior of the controlling valve h. The annular passage 1* is partially exposed inwardly by a slot U in thesleeve 0 which extends over a portion of the periphery. Another slot y which extends over approximately the-same portion of the periphery, is located in the sleeve 0 in the path of the oil reservoir p. To it corresponds a narrow passage w in the stationary inner portion a of the handle which leads to the cavity m.

-When the outer portion a of the handle together with the sleeve 0 connected thereto is brought into the position shown in Figs. 1, 5 and 6. the compressed air, which is ad mitted at the free end of the handle through the tube connected therewith to the hollow space m, flows through the passage 8 and the slot 0 in the sleeve 0 into the annular.

passage 1- and thence through the oblique passage 26 and the passage u into the interior of the controlling member or valve h. At the same time the opening to in the inner tube 2 of the handle communicates with the slot y of the sleeve and consequently with the receptacle space 7), so that oil passes out of the receptacle into the passage m and is carried along by the compressed air flowing past to the engine.

If the handle be turned toward the'right into the position shown in Figs. 5 and 6 the two passages s and at will be covered-- by the sleeve 0, and the admission of compressed air to the engine will be consequently cut off. At the same time the outlet opening to for the, oil will also be cut ofl by the sleeve 0, so that any further passage of oil over into the cavity 1% will be prevented. The cutting 0H of the oil supply simultaneously with the admission of compressed air is important, as otherwise during pauses in the working oil would continuously pass over intothe cavity m and a considerable loss of oil would thereby be caused Instead of arranging the groove j in continuation of the valve opening 2' of thesta tionary valve device, there may be arranged with the sameresult andv as shown in Fig.1

8 grooves running inthe opposite direction and forming continuations of the two inlet openings f and g on theiinner surface. of the hollow drum shatt, which arrangemenuhowthe supply of pressure fluid to compensate the loss through leakage.

2. In a rotary expansion-engine, the combination of a casing, a rotary member therein having apiston, ahollow shaft on which said member is mounted, 'a fluid supplypassage in the wall of said shaft, a stationary tubular controlling member located in the latter and having a corresponding fluid supply passage, and a narrow auxiliarygroove' in the controlling surface of said controlling member to form an extended connection between said fluid supply passages to continue the supply of pressure fluid to compensate the loss through leakage.

8. In a rotary expansion engine, the combination of a casing, a rotary drum mounted therein, a hollow shaftbn which said drum is mounted. slides located in longitudinal slots formed in the drum; substan tially parallel cam surfaces in the casing opposite the ends of the drum and in cons tact with the ends of the slides. a cylindrical controlling member in the shaft, fluid supply passages in the wall of the latteivnear said cam surfaces, correspond ng passages in said controlling member, and narrow auxiliary passages arranged to form continuations of the fluidsupply passages of the con-' trolling member to continue the supply of pressure fluid to compensate the loss through leakage.

4b In. a rotary expansionv engine, the come ply passages in the Wall of the latter near said cam surfaces, corresponding passages in sald controlling member, and narrow aux- 'iliary passages in said controlling member 7 arranged to form continuations of the fluid supply passages of the controlling member to continue the supply of pressure fluid to '15 compensate the loss through leakage.

In testimony whereof, I affix my signature,

in presenceof two Witnesses.

RUDOLF EISERMANN. Witnesses: 7

AUGUST TRAUTMANN, V 'HENRY HASPER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

, Washington, D. 0. r V 

